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United States Patent |
5,642,804
|
Kellis
|
July 1, 1997
|
Pulley brake
Abstract
An improved braked pulley assembly for an endless conveyor including a
pulley body, a pair of gearboxes, and a pair of hydraulic braking members.
The gearboxes have bodies affixed to relatively opposite ends of the
pulley body and rotate with the pulley body. The hydraulic braking members
are laterally adjacent the pulley body and include an output shaft which
is mechanically coupled to an input shaft of an associated gearbox.
Actuation of the braking members transfers braking forces to the gearbox
inputs and to the pulley body to permit controlled slowing of the pulley
body rotational speed and, hence, a conveyor mounted thereon. The braked
pulley assembly is specially adapted for use in conveyor assemblies which
have limited available area for braking mechanisms, and which will not
accommodate conventional disc brake/caliper assemblies.
Inventors:
|
Kellis; John K. (Winfield, AL)
|
Assignee:
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Continental Conveyor & Equipment Co., L.P. (Winfield, AL)
|
Appl. No.:
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685166 |
Filed:
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July 23, 1996 |
Current U.S. Class: |
198/832.2 |
Intern'l Class: |
B65G 023/00 |
Field of Search: |
198/832.2,835
|
References Cited
U.S. Patent Documents
2421056 | May., 1947 | Dake et al. | 198/832.
|
3122945 | Mar., 1964 | Chung.
| |
3470992 | Oct., 1969 | Lagemann.
| |
3511350 | May., 1970 | Vom Stein.
| |
3557925 | Jan., 1971 | Zulauf.
| |
4013166 | Mar., 1977 | Weady et al.
| |
4047452 | Sep., 1977 | Eddy.
| |
4082180 | Apr., 1978 | Chung.
| |
4168611 | Sep., 1979 | Woyton et al.
| |
4223775 | Sep., 1980 | Lloyd.
| |
4548316 | Oct., 1985 | Maurer | 198/832.
|
4588065 | May., 1986 | Maiden et al.
| |
4821873 | Apr., 1989 | Crane.
| |
5147020 | Sep., 1992 | Scherman et al.
| |
Primary Examiner: Bidwell; James R.
Attorney, Agent or Firm: Pearne, Gordon, McCoy & Granger LLP
Claims
What is claimed is:
1. A braked pulley assembly for an endless conveyor, comprising:
a pulley body, said pulley body being generally hollow and cylindrical in
shape;
a gearbox mounted within the hollow interior of the pulley body, said
gearbox having an input shaft and a body, said gearbox body being
concentric with said pulley body and secured to said pulley body for
common rotation therewith, said gearbox body being operably interconnected
to said input shaft such that rotation of said input shaft is communicated
to said gearbox body and said pulley;
a hydraulic brake mounted laterally adjacent said pulley body and having an
output shaft, said output shaft being aligned with said input shaft and
being mechanically coupled to said gearbox input shaft for mutual rotation
about a common axis, said hydraulic brake being operable in either an
actuated, non-braking mode or an at-rest, braking mode;
wherein switching of said hydraulic brake from said actuated to said
non-actuated modes of operation decreases a rotational speed of said brake
output shaft and causes a rotational speed of the gearbox and the pulley
body to decrease.
2. A pulley brake assembly according to claim 1, wherein the gear box input
shaft and output shaft are rotationally coupled and rotate at a first
speed, and wherein said gearbox body and pulley body rotate at a second
speed which is different than said first speed.
3. A pulley brake assembly according to claim 2, wherein the second speed
is proportional to, but slower than, the rotational speed of the output
shafts.
4. A pulley brake assembly according to claim 2, wherein said input shaft
is connected to said gearbox body by a differential gear drive assembly.
5. A pulley brake assembly according to claim 4, wherein said differential
gear drive assembly includes an input pinion secured to the input shaft, a
differential gear, and a ring gear, said differential gear having a first
portion coupled to the input pinion and a second portion coupled to the
ring gear.
6. A pulley brake assembly according to claim 5, wherein the ring gear is
secured to the gear box body for mutual rotation.
7. A pulley brake assembly according to claim 6, wherein said first portion
has a first diameter and said second portion has a second diameter, said
first diameter being smaller than said second diameter.
8. A braked pulley assembly for an endless conveyor, comprising:
a pulley body, said pulley body having first and second ends;
a first gearbox mounted within said first end of said pulley body, said
first gearbox having an input shaft and a body, said first gearbox being
generally concentric with said pulley body and secured to said pulley body
first end for common rotation therewith, said first gearbox body being
operably interconnected to said first gearbox input shaft such that
rotation of said first gearbox input shaft is communicated to said first
gearbox body and said pulley;
a second gearbox mounted within said second end of said pulley body, said
second gearbox having an input shaft and a body, said second gearbox being
generally concentric with said pulley body and secured to said pulley body
second end for common rotation therewith, said second gearbox body being
operably interconnected to said second gearbox input shaft such that
rotation of said second gearbox input shaft is communicated to said second
gearbox body and said pulley;
a first hydraulic brake mounted adjacent said pulley body and having an
output shaft, said first brake output shaft being aligned with said first
gearbox input shaft and laterally spaced from said first end of said
pulley body, said first brake output shaft being mechanically coupled to
said first gearbox input shaft for rotation about a common axis, said
first hydraulic brake being operable in either an actuated, non-braking
mode or an at-rest, braking mode;
a second hydraulic brake mounted adjacent said pulley body and having an
output shaft, said second brake output shaft being aligned with said
second gearbox input shaft and laterally spaced from said second end of
said pulley body, said second brake output shaft being mechanically
coupled to said second gearbox input shaft for rotation about a common
axis, said second hydraulic brake being operable in either an actuated,
non-braking mode or an at-rest, braking mode;
wherein switching of said first and second hydraulic brakes from said
actuated to said non-actuated modes of operation decreases a rotational
speed of said first and second brake output shafts and causes a rotational
speed of the first and second gearbox bodies and the pulley body to
decrease.
9. A pulley brake assembly according to claim 8, wherein the first gearbox
input shaft and said first brake output shaft are rotationally coupled to
one another and rotate at a first speed, said second gearbox input shaft
and said second brake output shaft are rotationally coupled to one another
and rotate at said first speed, and wherein said first and second gearbox
bodies and said pulley body rotate at a second speed which is different
than said first speed.
10. A pulley brake assembly according to claim 9, wherein the second speed
is proportional to, but slower than, the first speed.
11. A pulley brake assembly according to claim 9, wherein each gearbox
input shaft is connected to an associated gearbox body by a differential
gear drive assembly.
12. A pulley brake assembly according to claim 11, wherein said
differential gear drive assembly includes an input pinion secured to the
input shaft, a differential gear, and a ring gear, said differential gear
having a first portion coupled to the input pinion and a second portion
coupled to the ring gear.
13. A pulley brake assembly according to claim 12, wherein each ring gear
is secured to an associated gearbox body for mutual rotation.
14. A pulley brake assembly according to claim 13, wherein said first
portion has a first diameter and said second portion has a second
diameter, said first diameter being smaller than said second diameter.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to pulleys and, more particularly,
to braked pulleys used in endless conveyors.
2. Description of Related Art
Braked pulleys are used on endless conveyors to help bring the conveyor to
a stop. Braked pulleys are conventionally used on most mining conveyors,
such as fixed conveyors and mobile or long-run conveyors, and are
necessary on down-hill conveyors. Such braked pulleys conventionally
provide a pulley body which is mounted upon a pulley shaft, the pulley
body and pulley shaft being joined at ends of the pulley body to force the
pulley body to rotate with the pulley shaft. Ends of the pulley shaft
project from the pulley body, each end having a brake disc mounted
thereon. The brake disc is selectively engaged by brake pads mounted to
spring or hydraulically actuated brake calipers and, as such, the overall
design of braking assemblies used on conventional endless conveyor braked
pulleys generally conforms with the design of disc brakes commonly used in
automotive applications.
Such conventional braked pulleys have the braking mechanism exposed to
dirty and harsh environments, which tends to limit the useful life of the
brake components. Moreover, in applications wherein the conveyor is to be
stopped repeatedly, heat generated from frictional engagement between the
brake pads and the brake disk has, in the past, caused the braking
mechanism to over-heat and fail. As such, regular replacement in high-use
applications is common.
The aforementioned conventional braking systems also suffer from structural
disadvantages which render their use less than desirable, and has, in some
applications, rendered their use impossible. For example, in some fixed
conveyor applications, there is limited available space at each end of the
conveyor pulley. The conventional design requires the brake discs/calipers
to be laterally outboard of the pulley body. As such, inclusion of the
aforementioned conventional braking system on some fixed conveyor
installations has been problematic, and has resulted in less than optimal
installations.
Furthermore, in mobile conveyors, there is not enough space laterally
outboard of the pulley body to accommodate the brake discs/calipers.
Moreover, in mobile conveyors the conveyor must be stopped often to permit
advance/retreat of the conveyor, and the conventional braking system tends
to overheat upon repeated use and, therefore, is ill-suited to repeatedly
stop the conveyor, as discussed previously. As such, the aforementioned
conventional braked pulleys and pulley braking systems are not practically
useful in such applications.
Therefore, there exists a need in the art for a braked pulley and a braked
pulley system which is dimensionally smaller, and which does not occupy a
significant amount of space laterally of the pulley body. There also
exists a need in the art for a braked pulley which is useful in
installations wherein spacial constraints prevent large exterior braking
assemblies from being used. There also exists a need in the art for a
braked pulley which is adapted for the harsh and dirty conditions of a
mine, and which is adapted for repeated use without overheating.
SUMMARY OF THE INVENTION
The present invention is directed toward a braked pulley which is of
reduced size and toward a pulley braking system which is useful on endless
conveyors which will otherwise not accommodate a braked pulley due to
spacial constrains. The present invention is also directed toward a braked
pulley which can be repeatedly used without overheating, and wherein the
braking elements are sealed or enclosed, and are not degraded or damaged
by contamination in dirty environments.
In accordance with the present invention, a braked pulley assembly for an
endless conveyor includes a pulley body, a gearbox, and a hydraulic brake.
The pulley body is generally hollow and cylindrical in shape and has the
gearbox mounted within the hollow interior thereof. The gearbox has an
input shaft and a body. The gearbox body is concentric with the pulley
body and is secured to the pulley body for common rotation therewith. The
gearbox body is operably interconnected to the input shaft such that
rotation of the input shaft is communicated to the gearbox body and the
pulley.
In further accordance with the present invention, the brake is located
laterally adjacent the pulley body and has an output shaft which is
aligned and mechanically coupled to the gearbox input shaft for mutual
rotation about a common axis. The brake is operated in either an actuated,
non-braking mode or an at-rest, braking mode.
In further accordance with the present invention, switching of the
hydraulic brake from the actuated to the non-actuated modes of operation
decreases a rotational speed of the brake output shaft and the gearbox
input shaft and causes a rotational speed of the gearbox and the pulley
body to decrease.
BRIEF DESCRIPTION OF THE DRAWINGS
These and further features of the present invention will be apparent with
reference to the following description and drawings, wherein:
FIG. 1 is a schematic end elevational view of a pulley assembly according
to the present invention;
FIG. 2 is a schematic top plan view of a pulley assembly according to the
present invention;
FIG. 3 is a cross-sectional view of a hydraulic brake according to the
present invention; and
FIG. 4 is a cross-sectional view of a gear box according to the present
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
With reference to the drawing figures and, in particular, FIG. 1, a braked
pulley assembly 10 according to the present invention is illustrated. The
braked pulley assembly 10 includes a pulley body 12, first and second
gearboxes 14, 16, first and second hydraulic brake assemblies 18, 20, and
first and second mounting brackets 22, 24. As will be apparent from the
discussion to follow, the preferred and illustrated braked pulley assembly
10 according to the present invention is adapted for use at a tail portion
of an endless conveyor assembly, preferably in conjunction with a mobile
or advancing conveyor incorporating a conveyor belt accumulator assembly.
Such a conveyor must be periodically stopped to permit advancement or
retreat of the operating length of the conveyor as is necessary during a
continuous mining/conveying operation.
The pulley body 12 is generally cylindrical and hollow, and has an outer
surface 26 over which a conveyor belt (not shown) moves. The pulley body
has first and second ends 28, 30 in which the first and second gearboxes
14, 16 are disposed, respectively. The first and second ends 28, 30 each
include an annular rim 32 which is secured to an associated gearbox 14, 16
such that the gearboxes and pulley body 10 are rotationally linked, as
will be described more fully hereafter.
With reference to FIG. 4, the first gearbox 14 is illustrated, it being
understood that the second gearbox 16 is preferably identical thereto. The
first gearbox 14 has a hub spindle member 34, a cover member 36, and a
mounting adapter member 38. The cover member 36 is secured, preferably by
bolts, to the spindle member 34, and cooperates with the spindle member 34
to define a hollow body 37 of the gearbox 14.
The spindle member 34 has a radial mounting flange 40 which is affixed to
the annular rim 32 provided at the associated first end 28 of the pulley
body 12. Preferably, the gearbox mounting flange 40 is bolted to the
pulley body annular rim 32 and thereby rotates coaxially and at a common
speed with the pulley body 12. An end of the gear box 14 opposite the
cover member 36 is closed by the mounting adapter member 38 which is
secured to a mounting bracket 22 (FIGS. 1 and 2) and through which an
output shaft 44 of the first hydraulic brake assembly 18 extends.
Disposed within the gearbox hollow body 37 is a differential planetary
wheel drive assembly 46 which transfers braking forces from the brake
assembly 18 to the gearbox body 37, the pulley body 12, and the conveyor
belt mounted thereover. The planetary wheel drive assembly 46 includes an
input shaft 48, a coupling member 50 which couples the input shaft 48 to
the brake assembly output shaft 44 for mutual rotation, an input pinion
gear 52 secured to the input shaft 48, a differential gear 54, an internal
gear 56, and a ring gear 58 secured to the gearbox body 37.
The input shaft 48 extends from the mounting adapter member 38 into the
interior of the gearbox 14 and toward the cover member 36. A first end of
the input shaft 48 is secured to the coupling member 50 disposed within a
recess in the mounting adapter member 38. An opposite or second end of the
input shaft 48 is rotationally journalled to the cover member 36 by a
bearing member 49, as illustrated.
Intermediate the first and second ends of the input shaft 48, the input
pinion gear 52 is affixed over the input shaft. First and second thrust
spacers 60, 62 are disposed over the shaft 48 on laterally opposite sides
of the input pinion gear 52. The first thrust spacer 60 is engaged by a
spring 64 which is disposed around the input shaft 48 and received within
an enlarged recess provided at an inner end of the mounting adapter member
38.
The input pinion gear 52 is coupled to the differential gear 54. The
differential gear 54 is mounted upon a shaft 66 which is secured within
the hollow body by a carrier assembly 68. Bearings are provided between
the differential gear 54 and the shaft 66, as illustrated. The
differential gear 54 includes a first smaller diameter portion 70 coupled
to the input pinion gear 52 and the internal gear 56, and a second, larger
diameter portion 72 coupled to the ring gear 58. The ring gear 58 is
secured to the gearbox body intermediate the hub spindle assembly 34 and
the cover member 36. As such, the gearbox body 37 and ring gear 58 are
affixed to one another for mutual rotation about an axis defined by the
input shaft 48.
With reference to FIG. 3, the first hydraulic brake assembly 18 is
illustrated, it being understood that the second hydraulic brake assembly
20 is identical thereto. The first hydraulic brake assembly 18 includes a
housing 74 which defines a hollow chamber in which a wet-disk type brake
is disposed. The brake assembly housing 74 includes first and second end
caps 76, 78, the mounting adapter 42 and a cylindrical main body portion
80 intermediate the first and second end caps 76, 78. The end caps 76, 78,
mounting adapter 42 and main body portion 80 are preferably bolted
together to form a unitary assembly. The brake assembly mounting adapter
42 is preferably secured to the gearbox mounting adapter 38 by bolts and
cooperation of aligned annular projections 41 and grooves 43, as
illustrated.
The second end cap 78 includes a coolant inlet port 82 and at least one
hydraulic actuation fluid inlet port 84. Cooling fluid is introduced into
the hollow chamber of the housing 74 via the coolant inlet port 82 and
exits the housing 74 from a radial coolant outlet port (not shown).
Pressurized hydraulic fluid is introduced via the actuation fluid inlet
ports 84 into a brake actuator assembly 86, as will be described more
fully hereafter.
Partially disposed within the hollow chamber defined by the housing 74 is
the output shaft 44, which projects through the second end cap 78 and the
mounting adapter 42, a plurality of drive plates 88, a plurality of
friction discs 90, and the brake actuator assembly 86. The output shaft 44
has a hollow, perforated inner end disposed within the hollow chamber.
The friction discs 90 are annular members affixed to and radially
projecting from the inner end of the output shaft 44, as illustrated. The
drive plates 88 are annular members interleaved or interposed between
adjacent friction discs 90. Perforations or holes provided through the
inner end of the output shaft 44 permit cooling fluid to circulate through
the housing interior, including around the drive plates 88 and friction
discs 90. A cooling fluid outlet (not shown) is preferably provided at a
radial surface of the housing 74.
The drive plates 88 are connected to a generally cylindrically-shaped
piston member 92 provided by the brake actuator assembly 86, and move into
and out of engagement with the friction discs 90 upon corresponding
movement of the piston member 92, as will be described more fully
hereafter. Separator springs 94 are disposed between adjacent drive
plates, and maintain the drive plates 88 a distance from one another.
The brake actuator assembly 86 includes, in addition to the piston member
92, a plurality of biasing springs 96, and an annular member 98. The
annular member 98 is concentric with the piston member 92 and cooperates
with the cylindrical piston member 92 to define an actuation chamber 100.
Passages 102, corresponding in number to the number of actuation fluid
inlet port(s) 84, are formed through the annular member 98 to communicate
pressurized fluid from the inlet port(s) 84 to the actuation chamber 100.
The biasing springs 96 urge the piston member 92 toward a normal or
at-rest position in which the drive plates 88 engage the friction discs
90. The piston member 92 is moved to an actuated position in which the
drive plates 88 are disengaged from the friction discs 90 by pressurized
actuation fluid introduced into the actuation chamber 100 via the inlet
port(s) 84 and passage(s) 102.
When pressurized actuation fluid is introduced into the actuation chamber
100, the piston member 92 and drive plates 88 are moved against the spring
bias, and the drive plates 88 are moved out of engagement with the
friction discs 90. When pressurizing fluid is discontinued or cut off to
the actuation chamber 100, the spring 96 returns the piston member 92 to
the at-rest position wherein the drive plates 88 engage the friction discs
90. Frictional engagement between the drive plates 88 and the friction
discs 90 quickly slows and stops rotation of the brake output shaft 44,
the gearbox input shaft 48 connected thereto, and the pulley 12 secured to
the gearbox, and the conveyor belt.
The arrangement wherein discontinuation of pressurized fluid brings about
stopping of the pulley is preferred insofar as the pulley body 12 and
conveyor belt will be stopped should a power or system component failure
occur, i.e., pump failure, power outage, rupturing of a hydraulic line.
Naturally, it is contemplated that the arrangement could be reversed such
that the at-rest or normal position of the piston member is disengaged (no
braking) and the actuated position is engaged (braking).
The braking surfaces (i.e., drive plates 88 and friction discs 90) are
completely enclosed and isolated from the surrounding environment, and
therefore are not damaged by dirt or other environmental conditions. The
continuous flow of cooling fluid keeps the brake assemblies 18, 20 cool,
and prevents overheating thereof. The assembly 10 is dimensionally small,
and therefore adapted for use in conveyor assemblies, such as mobile
conveyors, wherein space is at a premium. Moreover, the assembly 10 is
adapted for repeated use, and quickly slows an associated conveyor belt
from an operating speed to a complete stop.
While the preferred embodiment of the present invention is shown and
described herein, it is to be understood that the same is not so limited
but shall cover and include any and all modifications thereof which fall
within the purview of the invention. For example, in a down-hill type
endless conveyor wherein the conveyed material and the conveyor belt
develop significant inertia resisting stopping, a plurality of braked
pulley assemblies according to the present invention may be used.
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